Recovery from iron ore of secondary metal



Patented Nov. 10, 1942 2.3o1,492 nncovnnr FROM IRON one or snconmarMETAL John L. Young, Pittsburgh, Pa, 'assignor, by mesne assignments, toPlastic Metals, Inc., a corporation of New York No Drawing. ApplicationNovember 10, 1938, Serial No. 239,895

2 Claims.

This invention relates to the recovery, from ores and oxides derivedfrom industrial operations in which both iron and another metal arepresent, the two metals.

In a companion application for Letters Patent filed by me October 22,1938, Serial No. 236,589, for an invention described in an earlier andforfeited application, filed March 13, 1937, Serial No. 130,715, I havedescribed the preparation of an anode for an electrolytic cell. Theanode may be prepared from granulated sponge iron. A body of suchmaterial is shaped and compressed, and in compressed condition isbrought while in a reducing atmosphere to bright-annealing temperature.Under such conditions surface oxides are reduced, metallic bridges areformed between the grains, and the result is a porous anode of highconductivity throughout its mass. An anode of sponge iron is describedalso in Letters Patent 2,043,823 granted June 9, 1936, on myapplication.

In Letters Patent of the United States No. 2,102,249, the jointinventors, of whom I am one, have described the production of an anodeby the compression of discrete bodies of iron coated with another metal,and by heating the compressed mass until the coating metal forms bridgesbetween the constituent bodies. In this case, too, a porous anode isformed of high conductivity. In the electrolytic operation it was foundthat the iron of the anode of the lastnamed patent could be taken intosolution by the electrolyte, while the coating metal (typically tin)would fall away and would collect with the slime in the bottom of thecell, and from that slime the coating metal manifestly could berecovered.

I now have discovered that, beginning with native ore (or, indeed, withoxide derived from other industrial operations) in which iron is foundin association with another metal, and proceeding along lines pursued insuch other connection, I may not only recover the iron in pure state,but I may eifect a substantially clean out, between the iron and theother metal present in the ore; and I may recover fromv the slimedeposited in the electrolytic cell such other metal,

in reduced or combined state according to circumstances. For instance, Imay so recover in metallic state copper present with iron in the ore (oroxide), or, again, I may so recover titanium, in the state of oxide.

I have found it to be characteristic of my procedure that the degree ofpressure may be emof the anode correspondingly fixed, so that the ironwill pass freely and fully into solution in they electrolyte,to bedelivered thence as a cathode deposit, while the remaining constitutentsof the substance of the anode will slough freely OE and be deposited asslime in the bottom of the cell, and the electrolytic operation will goforward continuously and without choking.

Beginning with ore (or equivalent oxide) in finely divided or granularcondition, I first bring itin a reducing atmosphere to iron-oxidereducing temperature, and in so doing I convert the iron oxide orsubstantial portions thereof to me tallic iron. I thin, whilemaintaining the temperature and the reducing atmosphere, compress thegranular material and form of it a coherent but still porous mass.Conveniently the mass is pressed upon a core of clean-surfaced metal,and the adjacent grains are thus brought into electric union with thecore, while under the same pressure contiguous particles within the massare brought into electric union one with another. The core serves, ofcourse, as a pole piece in the assembly of the anode in an electrolyticcell. A core is not, however, necessary; the granular material may becompressed to a coherent anode body without it.

The so completed anode is allowed to cool and is then brought into theopen air. It is assembled with a suitable cathode in an electrolyticcell, and an electrolyte, preferably a solution of ferrous and ammoniumsulphate, is provided.

Current being then applied, the iron of the anode will progressively gointo solution; a pure deposit of iron will progressively be laid on thecathode; the other constitutents of the anode body will progressivelyslough away and will collect in the slime at the bottom of the cell; andthe anode will continuously present a fresh surface, uncoated byresidual'material, to the continued vigorous action of the electrolyte.

The slime collected from thebottom of the cell will contain the othercomponents of the ore (or oxide) remaining after the iron-oxidereduction operation, such as sand and other material of stony nature,commonly called gangue, and it will also contain either in reduced orcombinedstate such other metallic component or components as may haveexisted in, the ore; as, for example copper (in reduced and metalliccondition) or titanium (still unreduced andin the condition of oxide).Such metallic content of the slime may then by subsequent knownpropix-ically determined, and the degree of porosity cedure berecovered.

I have specified an electrolyte of ferrous and ammonium sulphate. Thereare iron oreswthati will admit of the use of an electrolyte of asolution of iron chloride; but it is only in exceptional cases that aniron chloride bath will serve. Ordinarly, the use of iron chloride willresult in the appearance at the cathode not of iron alone, but of othermetal also.

I have said that the degree of compression must, for a particular ore,be empirically determined. If the compression be carried too far and theanode be too densely compacted, it will as electrolysis progressesbecome coated with refuse material, to the embarrassment of theelectrolytic operation; if, on the other hand, it be insuflicientlycompressed,- an excessive amount of iron will be carried into the slime.

I am aware that it has been proposed to use as an anode loose spongeiron held in a suitable conmore, undissolved sulphide gathers in theslime in quantities such as would become an embarrassment to recovery ofany secondary metal therefrom. No attempt has heretofore been made insuch manner to separate from the iron a secondary metal present in theanode material. If sponge iron be melted and cast or rolled, anysecondary metal present would be so far alloyed with the iron as to beinseparable by such methods of electrolysis as here are contemplated. Noattempt has heretofore been made to effect separation from the iron of asecondary metal present in an anode so formed.

and employing that body as an anode in an electrolytic cell, with theresult that the iron goes to the cathode and the secondary metal passeswith a free-sloughing residue to the slime at the bottom of the cell. Ibelieve I am the first to find that the combination of a sulphate bathwith a suitable sponge iron anode will give a pure cathode deposit and asecond component, recoverable from the slime.

I claim as my invention:

1. The method herein described of separating two metallic components ofan iron ore, which consists in bringing the ore in finely dividedcondition into a reducing atmosphere and there subjecting it to reducingtemperature; then, when under such conditions the iron content has beenbrought to metallic state and while the conditions I believe myself tobe the first to discover the possibility of separating from the iron asecondary metallic component of an iron ore, or equivalent oxide, bygranulating the ore, reducing its iron content to metallic state,consolidating the sponge to a coherent and porous body,

(5 and carried with the residue to the slime in the of an inertatmosphere and an elevated temperature are maintained, compressing thematerial to a coherent porous body within which the iron continues infree and pure metallic state; and, finally, conducting an electrolyticoperation with such coherent porous body as the anode and with asolution of ferrous and ammonium sulphates as the electrolyte, in whichoperation the iron goes progressively into solution and is depositedon-the cathode, while the other constituents of the anode body areprogressively sloughed away and collect in the slime at the bottom ofthe cell.

2. The method herein described of recovering from an iron ore orequivalent oxide that contains also a secondary metallic content the twometals, separate each from the other, which consists in subjecting theraw material in finely divided condition to iron oxide reducingconditions and producing thereby within the mass pure metallic iron,compressing the material so treated while the conditions of an inertatmosphere and an elevated temperature are maintained to a coherentporous mass, conducting an electrolytic operation with such coherentporous mass serving as the anode, whereby the iron taken into solutionin the electrolyte is deposited at the cathode and the secondary metalis sloughedofi bottom of the cell, and recovering from the slime thesecondary metal.

JOHN L. YOUNG.

